I've read all the books several times. I've honestly been thinking about reading them again soon..and watching the movies again.
For the most part, the movies are good adaptations..but a few explanations here and there were left out.
I do like the books better. Certain things are just developed more. There are whole subplots that are missing from the movies...While I didn't mind some of them not being in the movies, a few others end up being more important.
Competely with you on this. The books are great in their own right. They do start out as 'young adult' but i think they, like the movies evolved very well. They are fun to read.
And the films, being adaptations of the books, did a very good job of putting most of the big bits in. By the end the films had become great in their own right.